A driver had to be cut out a car by fire crews after a crash at Clawddnewydd, near Ruthin, just before 10am. In another incident, a BMW and Vauxhall Astra collided near Holywell.

The Crimea Pass on the A470 between Blaenau Ffestiniog and Betws y Coed was particularly treacherous, with a Citroen car sliding off the road at Talywaenydd into a field at 9.33am.

In Trawsfynydd, a yellow Iveco pick-up skidded and hit a tree. Paramedics treated a woman at the scene for a shoulder injury. Another woman’s car skidded on ice on the A5 at Capel Curig.

No-one was seriously hurt in any of the incidents, and councils in Gwynedd and Denbighshire sent gritters out to replace salt swept away by rain.

Weather forecasters warned the freezing rain could turn to snow last night, as temperatures were expected to drop as low as -7°C – especially in north east Wales.

A police spokesman said the roads were very slippery in the Blaenau Ffestiniog area and several motorists had difficulties.

One van driver said: “The road up the Crimea from Roman Bridge was like a sheet of ice. When I pulled into a layby I couldn’t stand up and had to get out (of the van) on the passenger side and onto the grass verge. Once the gritters went past the road was just about passable.”

A Denbighshire council spokesman said: “No major problems have been reported on Denbighshire roads overnight and the council’s gritting teams have been busy treating roads across the county overnight and this morning. The council regularly monitors the weather situation and teams are deployed to treat roads when wintry weather is forecast.”

A Gwynedd council spokeswoman added: “On Thursday morning, scheduled gritting took place along 11 priority routes in Meirionnydd at 5am. Between 8am and 8.30am, further rain fell and froze immediately as the ground was so cold.

“All the council’s gritting teams were out again during the morning and a warning was issued through Traffic Wales advising motorists to take care while driving.”

A Met Office spokesman said freezing rain occurs when droplets fall through air with a temperature below zero. They then freeze on impact with the ground, forming a clear ice known as a “glaze”.

Freezing rain can make untreated surfaces very slippery and sometimes the ice cannot be seen so it can be very dangerous.

Mark Peacock, head of AA Driving School, added: “Driving conditions will be treacherous in many parts over the next few days, with ice and snow predicted for many regions. It’s more important than ever to plan journeys carefully and heed any police warnings on whether to drive.

“If motorists do make a journey it is absolutely vital to adjust the driving to suit the conditions.

“The key is to go easy, drive with extra care and keep the car moving smoothly, avoiding sudden movements with the steering wheel, brakes or accelerator.”